KR102863163B1 - Systems and methods for multipath beam nulling - Google Patents

Abstract

A radar system and method for reducing multipath interference signals are provided. Multipath interference signals can be reduced by the radar system emitting electromagnetic waves that generate nulls in the direction of expected multipath interference signals, such that the multipath interference signals can be rendered null (or substantially null) from signals received by the radar system.

Description

Systems and methods for multipath beam nulling

The present invention relates generally to radar systems, and more particularly to reducing multipath interference in radar systems.

Radar systems (e.g., radar) can be used to detect objects. For example, radar systems can be used on aircraft, ships, and/or ground vehicles to detect objects. Different radar applications (e.g., terrestrial, airborne, maritime, military, commercial, etc.) may have different requirements and constraints for radar systems. Typical radar requirements may include the ability to detect objects within a specific field of view, range, and/or altitude with a specific accuracy and/or sensitivity.

A radar system typically includes an emitter and a receiver. The emitter can transmit electromagnetic waves (e.g., a beam) from the radar system, sometimes in a specific direction. The electromagnetic waves can strike an object, causing at least some of the waves to reflect back toward the radar system and be received by the receiver.

One challenge for radar systems involves multipath interference. Multipath interference can occur when emitted electromagnetic signals reflect from objects of interest (e.g., desired detection targets) as they travel to and/or from them. Examples include ground, mountains, buildings, and/or bodies of water. Electromagnetic signals can reflect back to the radar system from interfering objects, resulting in incorrect angles of arrival, leading to false object detection (e.g., ghost detection), and possibly disrupting the detected angles of arrival of the desired target signal. Multipath returns can also increase the apparent length of a target, making target identification (e.g., combat) inaccurate. For example, cruise missiles may be misclassified as aircraft, altering the target's estimated lethality. Incorrect lethality of an object can cause combat systems guided by the radar system to incorrectly engage or fail to engage the target.

False targets can divert radar resources from desired missions and/or increase the number of tracks maintained by the radar system, which can lead to delays in radar processing time. Multipath can also increase or decrease the signal-to-noise ratio, which can contribute to the likelihood of tracks being lost. Incorrectly clearing tracks typically allows the radar to detect objects again, artificially increasing the number of track changes. This can further impact radar resources, for example, by reacquiring/initiating new tracks.

Therefore, it may be desirable to reduce multipath interference signals in radar systems.

Advantages of the present invention may include the elimination and/or substantial elimination of multipath interference. Other advantages of the present invention may include improvements in track accuracy, track continuity, combat identification, and/or improved radar resource allocation.

In one aspect, the present invention comprises a method for reducing multipath interference. The method may include determining, by a radar system, a first set of digital beamforming weights based on a desired direction of one or more analog beams of the radar system, a desired direction of one or more digital beams, and an expected direction of the multipath interference signal. The method may also include determining, by the radar system, a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null in each of the one or more digital beams in the direction of the multipath interference signal. The method may also include applying, by the radar system, the second set of digital beamforming weights during a reception period of the radar system such that signals received by the radar system are free of the multipath interference signal.

In some embodiments, the step of determining the first set of digital beamforming weights further comprises the step of determining, by the radar system, an elevation angle of the multipath interference signals. In some embodiments, the step of determining the first set of digital beamforming weights further comprises the step of determining a location of the multipath interference signals.

In some embodiments, the method includes determining, by the radar system, a location of a target based on a plurality of reflected signals; determining, by the radar system, a distance between the location of the multipath interference signal and the location of the target; and setting the location of the multipath interference signals to the minimum distance value if the distance is less than a minimum distance.

In some embodiments, the step of determining the second set of digital beamforming weights further comprises: determining, by the radar system, a first voltage of each digital beam of the radar system in the direction of the multipath interference signals; and determining, by the radar system, a second voltage of a nulling digital beam of the radar system in the direction of generating the nulls.

In some embodiments, the first voltage, the second voltage, or both are complex numbers. In some embodiments, the radar system is a digital beamforming radar. In some embodiments, the method further comprises the step of outputting, by the radar system, the signals received by the radar system to a display.

In another aspect, the present invention comprises a radar system for reducing multipath interference. The radar system may include one or more antenna arrays, each antenna array including a plurality of antennas capable of transmitting and receiving electromagnetic signals. The radar system may include a processor coupled to the one or more antenna arrays. The processor may be configured to determine a first set of digital beamforming weights based on a desired direction of one or more analog beams of the radar system, a desired direction of one or more digital beams, and an expected direction of the multipath interference signal, determine a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null for each of the one or more digital beams in the direction of the multipath interference signal, and control the one or more antenna arrays to apply the second set of digital beamforming weights during a reception period of the radar system such that signals received by the radar system are free of the multipath interference signal.

The radar system may further include a step of determining a first set of digital beamforming weights, the step further comprising a step of determining, by the radar system, an elevation angle of the multipath interference signals. The radar system may further include a step of determining a first set of digital beamforming weights, the step further comprising a step of determining a location of the multipath interference signals. The processor may further be configured to cause the radar system to determine a location of a target based on a plurality of reflected signals, determine a distance between the location of the multipath interference signal and the location of the target, and set the location of the multipath interference signals to the minimum distance value when the distance is less than a minimum distance.

In some embodiments, the processor may be further configured to determine a first voltage of each digital beam of the radar system in the direction of the multipath interference signals, and to determine a second voltage of a nulling digital beam of the radar system in the direction of generating the nulls.

In some embodiments, the first voltage, the second voltage, or both are complex numbers. In some embodiments, the radar system is a digital beamforming radar. In some embodiments, the radar system further comprises a step of outputting the signals received by the radar system to a display.

In another aspect, the present invention comprises a computer program product comprising instructions that, when the program is executed, cause a computer to determine a first set of digital beamforming weights based on a desired direction of one or more analog beams of a radar system, a desired direction of one or more digital beams, and an expected direction of a multipath interference signal; determine a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null in each of the one or more digital beams in the direction of the multipath interference signal; and apply the second set of digital beamforming weights during a reception period of the radar system such that signals received by the radar system are free of the multipath interference signal.

Non-limiting embodiments of the present disclosure are described below with reference to the accompanying drawings listed after this paragraph. The dimensions of the features depicted in the drawings have been selected for convenience and clarity of description and are not necessarily drawn to scale.
The subject matter considered to be the present invention is particularly pointed out and clearly claimed in the concluding portion of this specification. However, the present invention, both in terms of structure and method of operation, together with objects, features, and advantages thereof, may be understood by reference to the following detailed description when read in conjunction with the accompanying drawings. Embodiments of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, wherein like reference numerals represent corresponding, similar, or analogous elements, wherein:
FIG. 1 is an example of a radar system and an object according to some embodiments of the present invention.
FIG. 2 is a flowchart for a method for reducing multipath interference according to some embodiments of the present invention.
Figure 3 is a graph showing the output of a radar system that does not reduce multipath interference according to the prior art.
FIG. 4 is a graph showing the output of the radar system of FIG. 4 for reducing multipath interference, according to some embodiments of the present invention.
FIG. 5 is a high-level block diagram of an exemplary computing device that may be used with some embodiments of the present invention.
For simplicity and clarity, it should be understood that elements depicted in the drawings are not necessarily drawn precisely or to scale. For example, the dimensions of some elements may be exaggerated relative to others for clarity, or several physical components may be included in a single functional block or element.

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, modules, units, and/or circuits have not been described in detail to avoid obscuring the present invention.

In general, the present invention involves canceling multipath interference in a radar system and/or improving the accuracy of radar system detection. A radar system can emit and receive electromagnetic energy. Typically, a radar system uses part of its operation to emit (e.g., transmit) electromagnetic energy (e.g., signals) and part of its operation to receive (e.g., listen) electromagnetic signals. The emitted electromagnetic energy may impinge upon one or more objects, and at least a portion of the emitted electromagnetic energy may be reflected back to the radar system. In some scenarios, at least a portion of the reflected electromagnetic energy may be multipath interference (e.g., reflections from objects within the radar system's field of view that are not objects of interest to be tracked, such as buildings and/or the ground).

During the reception period, the radar system can null the direction (or approximate direction) of the multipath interference so that the multipath interference can be eliminated and/or substantially eliminated. By determining the direction from which the multipath interference is likely to reach the radar system, the multipath interference can be nulled, thereby reducing the impact of the multipath interference on the radar system's detection.

FIG. 1 illustrates an example of a radar system (100) and an object (110), according to some embodiments of the present invention. The radar system (100) can emit electromagnetic energy (e.g., a transmitted signal). When the transmitted signal collides with an object (110, 120), at least a portion of the transmitted signal is reflected from the object (110) and the object (120) (e.g., a mountain) and received by the radar system (100), allowing the radar system (100) to detect a false object in the direction of the object (120).

The radar system (100) may include one or more array(s) as is known in the art for performing analog and/or digital beamforming. For analog beam steering, the radar system (100) may have emitters/receivers that include, for example, phase shifters for steering the analog beam. The arrays of the radar system may be grouped into subarrays, and each element may be referenced by its position within a particular subarray. An element position may be referenced as x(m,n) and y(m,n), which are the element positions of element m in subarray n. For example, for subarray 3, element 2 may have a position of (2,3).

A radar system (100) can be aimed at a target location by analog beam steering. The analog beam steering can cause the radar system to point at the target location (e.g., in the direction of the analog beam of the radar system) and one or more reflected signals can be received. The reflected signal(s) can include a portion that is reflected from the target along a first path (e.g., a direct receive path) and a portion that is due to multipath interference along a second path (e.g., an indirect receive path). The location of the target can be defined in range, azimuth, and elevation coordinates, or in ultraviolet (UV) coordinates, as is known in the art. For example, the location of the target can also be converted from an ultraviolet (UV) coordinate system to a sine space representation in terms of range, azimuth, and elevation, as is known in the art.

In some embodiments, the location of the target is determined by a range (R), azimuth ( ) and altitude ( ) can be defined as a coordinate system. (R, , ) The target coordinate system can be transformed into the sine space (u _rx , v _rx ).

In some embodiments, the multipath interference location is determined by the range (R _mp ), azimuth ( ) and altitude ( ) can be defined as a coordinate system. (R, , ) coordinate system, the multipath interference location can be transformed into the sine space (u _mp ,v _mp ).

In some embodiments, the multipath interference signals are assumed to have the same range and same azimuth as the target, and only the altitude of the multipath interference signals is determined.

In some embodiments, the altitude of multipath interference signals ( ) is determined as follows:

ⅰ) Determine the height ( h ₂ ) of the target above the spherical Earth. The height ( h ₂ ) of the target above the spherical Earth can be determined as follows:

where h ₁ is the height of the antenna above sea level (in meters), a _e is 4/3 of the Earth's radius (in meters) (e.g., ~8493.3 x 10 3 meters for a standard radio atmosphere), and R _d is the slant range of the target (e.g., multipath generation). is the direct path elevation (e.g., )am.

ⅱ) Determine the ground range from the radar system to the ground reflection point (G ₁ ). The ground range (G ₁ ) can be determined as follows:

Here, G is the total ground range to the target, and p and ξ are intermediate values that can be determined as follows:

ⅲ) The angle between the radar system, the center of the Earth and the ground reflection point ( ) determines the angle ( ) can be determined as follows:

ⅳ) Determine the distance (R ₁ ) from the radar to the ground reflection point. The distance (R ₁ ) can be determined as follows:

ⅴ) Altitude of multipath interference signals ( ) is determined.

The locations of the multipath interference signals are (R, , ) can be described. Multipath interference signals can be transformed into uv sine space, (u _mp ,v _mp ).

In some embodiments, multipath interference signals are determined as known in the art.

FIG. 2 is a flowchart for a method for reducing multipath interference according to exemplary embodiments of the present invention.

The method may include determining (step 220) a first set of digital beamforming weights based on a desired direction of one or more analog beams of the radar system (e.g., the radar system (100) described above in FIG. 1) and/or a desired direction of one or more digital beams. The desired direction of the analog beam may be based on a field of view that the radar system is intended to cover, an expected direction for a target, a user input, or any combination thereof. The desired direction of the one or more digital beams may be related to a desired direction of one or more analog beams of the radar system.

The first set of digital beamforming weights can be determined as follows:

Here W( n ) is a set of digital weights for targeting the analog beam of the radar system, n is a particular subarray of the radar system, and m is a particular element of subarray n. x _SA ( n ) and y _SA ( n ) are the "phase centers" of channel n, δ u (m) and δ v (m) are the received digital beam positions specified in (u,v) coordinates with respect to the commanded analog beam center, and λ is the wavelength.

The method may also include a step (step 220) of determining an expected direction of a multipath interference signal relative to a desired direction of one or more analog beams of the radar system. The expected direction of the multipath interference signal may be determined as in Equations 1 through 7 described above.

The method may also include a step (step 230) of determining a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null for each of the one or more digital beams in the direction of the multipath reflected signal.

The step of determining the second set of digital beamforming weights may include determining a set of beam weights to generate nulls in the expected direction of the multipath. For example, beam weights in the expected null direction may be determined as follows:

Here, W( n ) is a set of digital weights for steer- ing the analog beam of the radar system toward the target (e.g., digital weights that can set the direction of the analog beam of the radar system), u _null and v _null are sine-space locations of the null beam, e.g., sine-space locations as described below in Equations 10 and 11, respectively, x _SA ( n ) and y _SA ( n ) are the “phase centers” of channel n, and λ is the wavelength.

The sine space position of the null beam can be determined as follows:

Here, u _mp and v _mp are sine space locations of multipath interference received signals, and u _rx and v _rx are sine space locations of received signals based on analog beam steering aimed at the target location. In some embodiments, if the distance between the target location and the null location is less than a minimum distance ( minimumNullSeperation ), the sine space location of the null beam can be modified to separate from the target location. The minimum distance can be an input value. The minimum distance can be a minimum separation value between the null location and the target location that can ensure that nulling the multipath at least substantially negates nulling the received beam from the target. The distance between the target location and the null location (d _null ) can be determined as follows:

If d _null < minimumNullSeperation * beamwidthU , and d _null < minimumNullSeperation * beamwidthU , then u _null is replaced by minimumNullSeperation * (beamwidthU ) and v _null is replaced by minimumNullSeperation * (beamwidthV ), where beamwidthU and beamwidthV are the beamwidths of the radar system in the u and v dimensions, respectively, scaled by the radar frequency.

In some embodiments, the step of determining the second set of digital beamforming weights comprises: The step of determining an expected complex voltage ( V _MLE ) for each digital beam m of the radar system in the direction in which nulls should be generated (e.g., the direction of u _null , v _null as described above). The expected complex voltage ( V _MLE ) for each digital beam m can be determined as follows:

a) Step for determining the phasing per element for analog beam steering:

Here Is is a complex multiplier for element k of channel n having analog beam steering pointing to the position of .

b) Step of applying weights to the phase per element for analog beam steering as follows:

where N _SA is the number of subarrays of the radar system used for digital beamforming, N is the number of elements within the subarray of the radar system, and m is a specific digital beam. where u _null , v _null are sine space pointing directions pointing towards the null, W( n ) is a set of digital weights for steering the analog beam of the radar system towards the target, n is a particular subarray of the radar system, m is a particular element within subarray n , x _SA ( n ) and y _SA ( n ) are the "phase centers" of subarray (or channel) n, δ u (m) and δ v (m) are the received digital beam positions specified in coordinates (u,v) with respect to the commanded analog beam center, and λ is the wavelength. Equation (14) can be rearranged into Equation (15):

In some embodiments, the step of determining the second set of digital beamforming weights may also include the step of determining an expected complex voltage ( V _nulling ) of the digital nulling beam peak in the direction of the sine space pointing direction toward the _null ( u _null , v null). The expected complex voltage ( V _nulling ) of the digital nulling beam peak may be determined as follows:

In some embodiments, the step of determining the second set of digital beamforming weights also includes applying beam weights for generating nulls ( nullweights (n)), an expected complex voltage ( V _MLE ) for each digital beam m , and an expected complex voltage of a digital nulling beam peak ( V _nulling ) to nominal rosette beam weights to determine the second set of digital beamforming weights, for example:

The method may also include a step (step 240) of applying a second set of digital beamforming weights during a reception period of the radar system such that multipath interference signals are not received by the radar system. The step of applying the second set of digital beamforming weights may cause a null in a receive antenna pattern of the radar system to be formed in the direction (or substantially in the direction) of an expected multipath interference signal during the reception period of the radar system. In this manner, the radar system may suppress (or substantially suppress) receiving multipath interference signals.

The method may also include a step (step 250) of outputting signals received by the radar system to a display.

Figure 3 is a graph showing the output of a radar system according to the prior art that does not reduce multipath interference. In Figure 3, the radar system is tracking an aircraft at an altitude of 200 meters. Figure 4 is a graph showing the output of the radar system of Figure 3 that reduces multipath interference, according to some embodiments of the present invention. As can be seen in Figure 4, more stable measurements can be obtained by reducing multipath interference as described by embodiments of the present invention.

FIG. 5 is a high-level block diagram of an exemplary computing device that may be used with embodiments of the present invention. The computing device (300) may include a controller or processor (105), which may be or may include, for example, one or more central processing unit processor(s) (CPU), one or more graphics processing unit(s) (GPU or GPGPU), a chip or any suitable computing or computational device, an operating system (315), memory (320), storage (330), input devices (335), and output devices (340). Each of the modules and devices, such as the processors, modules, boards, integrated circuits, and other devices referred to herein, referenced above, may be or include a computing device such as that included in FIG. 2, although various units between these entities may be combined into a single computing device.

The operating system (315) may be or include any code segment designed and/or configured to perform tasks that coordinate, schedule, arbitrate, supervise, control, or manage the operation of the computing device (800), such as, for example, scheduling the execution of programs. The memory (320) may be or include, for example, random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous DRAM (SD-RAM), double data rate (DDR) memory chips, flash memory, volatile memory, non-volatile memory, cache memory, a buffer, a short-term memory unit, a long-term memory unit, or any other suitable memory unit or storage unit. The memory (320) may be or include a plurality of, possibly different, memory units. The memory (320) may store, for example, instructions for performing a method (e.g., code (325)), and/or data such as user responses, interrupts, etc.

The executable code (325) may be any executable code, such as an application, a program, a process, a task, or a script. The executable code (325) may be executed by the controller (305) under the control of the operating system (315). For example, the executable code (325), when executed, may cause the antenna to emit and/or receive radiation for processing according to embodiments of the present invention. In some embodiments, one or more computing devices (300) or components of the device (300) may be used for the multiple functions described herein. For the various modules and functions described herein, one or more computing devices (300) or components of the computing device (300) may be used. Devices that include components similar to or different from those included in the computing device (300) may be used and may be connected to a network and used as a system. One or more processor(s) (305) may be configured to perform embodiments of the present invention, for example, by executing software or code. Storage (330) may be or include, for example, a hard disk drive, a floppy disk drive, a compact disc (CD) drive, a CD-recordable (CD-R) drive, a universal serial bus (USB) device, or other suitable removable and/or fixed storage unit. Data such as commands, codes, NN model data, parameters, etc. may be stored in storage (330) and loaded from storage (330) into memory (320) where it may be processed by the controller (305). In some embodiments, some of the components illustrated in FIG. 2 may be omitted.

The input devices (335) may be or include, for example, a mouse, a keyboard, a touch screen or pad, or any other suitable device. It will be appreciated that any suitable number of input devices may be operatively connected to the computing device (300), as illustrated by block (335). The output devices (340) may include one or more displays, speakers, and/or any other output devices. It will be appreciated that any suitable number of output devices may be operatively connected to the computing device (300), as illustrated by block (340). Any applicable input/output (I/O) devices may be connected to the computing device (300), and for example, a wired or wireless network interface card (NIC), a modem, a printer or facsimile machine, a universal serial bus (USB) device, or an external hard drive may be included as input devices (335) and/or output devices (340).

Embodiments of the present invention may include one or more article(s) (e.g., memory (320) or storage (330)), such as a computer or processor non-transitory storage medium, or a computer or processor non-transitory readable medium, such as a USB flash memory, a disk drive, or memory, that encodes, contains, or stores computer-executable instructions, for example, instructions that, when executed by a processor or controller, perform the methods disclosed herein.

Those skilled in the art will recognize that the present invention can be embodied in other specific forms without departing from its spirit or essential characteristics. Therefore, the above-described embodiments should be considered in all respects as illustrative rather than limiting of the invention described herein. The scope of the present invention is therefore indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced herein.

In the foregoing detailed description, numerous specific details are set forth to provide a better understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, modules, units, and/or circuits have not been described in detail so as not to obscure the present invention. Some features or elements described in connection with one embodiment may be combined with features or elements described in connection with other embodiments.

Although embodiments of the present invention are not limited in this regard, discussions using terms such as, for example, “processing,” “computing,” “calculating,” “determining,” “setting,” “analyzing,” “examining,” and the like, may refer to operation(s) and/or process(es) of a computer, computing platform, computing system, or other electronic computing device that manipulates and/or transforms data represented as physical (e.g., electronic) quantities within the computer’s registers and/or memories into other data similarly represented as physical quantities within the computer’s registers and/or memories or other information non-transitory storage medium capable of storing instructions for performing the operations and/or processes.

Although embodiments of the present invention are not limited in this regard, the terms “plurality” and “a plurality” as used herein can include, for example, “multiple” or “two or more.” The terms “plurality” and “a plurality” can be used throughout the specification to describe two or more components, devices, elements, units, parameters, etc. The term “set” as used herein can include one or more items. Unless explicitly stated, the method embodiments described herein are not limited to a particular order or sequence. Additionally, some of the method embodiments or elements described may occur or be performed simultaneously, at the same time, or concurrently.

100: Radar system
110: Object
120: Object

Claims (17)

In a method for reducing multipath interference,
A method for determining, by a radar system, a first set of digital beamforming weights based on a desired direction of one or more analog beams of the radar system, a desired direction of one or more digital beams, and an expected direction of the multipath interference signal, wherein the step of determining the first set of digital beamforming weights comprises the step of determining a location of the multipath interference signal;
determining, by the radar system, a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null in each of the one or more digital beams in the direction of the multipath interference signal;
applying said second set of digital beamforming weights during a reception period of said radar system such that a signal received by said radar system is free of said multipath interference signals;
A step of determining the position of a target based on a plurality of reflected signals by the radar system;
A step of determining the distance between the location of the multipath interference signal and the location of the target by the radar system; and
If the above distance is less than the minimum distance value, a step of setting the location of the multipath interference signal to the minimum distance value
including,
method.
In the first paragraph,
The step of determining the first set of digital beamforming weights comprises:
A step of determining an elevation angle of the multipath interference signal by the radar system.
including more,
method.
delete delete In the first paragraph,
The step of determining the second set of digital beamforming weights comprises:
A step of determining, by the radar system, a first voltage of each digital beam of the radar system in the direction of the multipath interference signal; and
A step of determining a second voltage of a nulling digital beam of the radar system in a direction in which each of the nulls is generated by the radar system.
including,
method.
In paragraph 5,
The first voltage, the second voltage, or both,
Complex number,
method.
In the first paragraph,
The above radar system,
Digital beamforming radar,
method.
In the first paragraph,
A step of outputting the signal received by the radar system to a display by the radar system
including more,
method.
In a radar system to reduce multipath interference,
One or more antenna arrays, each antenna array comprising a plurality of antennas configured to transmit and receive electromagnetic signals; and
a processor coupled to one or more of the above antenna arrays;
Including,
The processor controls the one or more antenna arrays to:
Determining a first set of digital beamforming weights based on a desired direction of one or more analog beams of the radar system, a desired direction of one or more digital beams, and an expected direction of the multipath interference signal, wherein determining the first set of digital beamforming weights comprises determining a location of the multipath interference signal;
Determining a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null in each of the one or more digital beams in the direction of the multipath interference signal;
Applying the second set of digital beamforming weights during a reception period of the radar system so that a signal received by the radar system is free of the multipath interference signal;
Determine the position of the target based on multiple reflected signals;
Determining the distance between the location of the multipath interference signal and the location of the target; and
When the above distance is less than the minimum distance value, the location of the multipath interference signal is set to the minimum distance value.
Radar system.
In paragraph 9,
Determining the first set of digital beamforming weights,
wherein the processor is configured to determine the elevation angle of the multipath interference signal;
Radar system.
delete delete In paragraph 9,
The above processor,
Determining a first voltage of each digital beam of the radar system in the direction of the multipath interference signal; and
Further configured to determine a second voltage of the nulling digital beam of the radar system in the direction of generating each null,
Radar system.
In Article 13,
The first voltage, the second voltage, or both,
Complex number,
Radar system.
In paragraph 9,
The above radar system,
Digital beamforming radar,
Radar system.
In paragraph 9,
The processor is further configured to output the signal received by the radar system to a display.
Radar system.
In a computer program stored in a non-transitory computer-readable storage medium,
When the above computer program is executed, the computer is associated with the radar system:
Determining a first set of digital beamforming weights based on a desired direction of one or more analog beams of the radar system, a desired direction of one or more digital beams, and an expected direction of a multipath interference signal; wherein when the computer program is executed, the computer causes the computer to determine a location of the multipath interference signal to thereby determine the first set of digital beamforming weights;
Determining a second set of digital beamforming weights based on the first set of digital beamforming weights to generate a null in each of the one or more digital beams in the direction of the multipath interference signal;
Applying the second set of digital beamforming weights during a reception period of the radar system so that a signal received by the radar system is free of the multipath interference signal;
Determine the position of the target based on multiple reflected signals;
Determining the distance between the location of the multipath interference signal and the location of the target; and
When the above distance is less than the minimum distance value, the location of the multipath interference signal is caused to be set to the minimum distance value.
Contains commands to do,
A computer program stored on a non-transitory computer-readable storage medium.